BRIMONIDINE TARTRATE - A ONE-MONTH DOSE-RESPONSE STUDY

Background: Brimonidine tartrate is a relatively selective alpha(2)-ag onist that effectively reduces mean intraocular pressure (IOP) and the incidence of IOP spikes after laser trabeculoplasty. The authors were interested in evaluating the dose response of brimonidine when applie d topically for a longer duration in patients with elevated IOPs. Meth ods: The authors conducted a 1-month, multicentered, double-masked, ra ndomized, placebo-controlled, parallel clinical study in 194 patients with ocular hypertension or glaucoma (mean IOP, 25.6 +/- 3.2 mmHg). Th e authors administered three concentrations of brimonidine (0.08%, 0.2 %, and 0.5%) or placebo bilaterally every 12 hours for 1 month. The au thors evaluated the following parameters: IOP, heart rate, blood press ure, visual acuity, pupil size, basal tear secretion as well as patien t comfort at baseline, day 1, week 1, week 3, and week 4. Results: All concentrations of brimonidine significantly reduced IOP, compared to baseline and placebo, at all follow-up visits. Maximum mean IOP decrea ses from baseline of 20.8%, 27.2%, and 30.1% were observed for the 0.0 8%, 0.20%, and 0.5% treatment groups, respectively. On days 1 and 21, the 0.2% and 0.5% treatment groups exhibited significantly greater IOP decreases than did the 0.08% group. After the initial steep decline i n IOP, the effect decreased slightly and stabilized at day 14 at the l evel that was maintained throughout the study. The most frequent side effects reported were fatigue and dry mouth. No significant changes in heart rate were reported. Statistically significant decreases in mean blood pressure without clinical symptoms were observed within the 0.2 % and 0.5% treatment groups. Conclusion: Brimonidine 0.2% is well tole rated, efficacious, and shows potential as an agent in the long-term t reatment of elevated IOP.